BIOL 190 Lecture Notes - Lecture 30: Heterosis, Polyploid, Assortative Mating

• School: University of San Diego
• Department: Biology Courses
• Course: BIOL 190
• Professor: Leavitt, Dean

Document Summary

Species are groups of organisms that are reproductively isolated from other groups of organisms. Gene ow ties members of a species together. Lack of gene ow allows species to evolve independently. Gene ow occurs between branches, but not across nodes. If a photo of every male father, grandfather, get grandfather, etc. were stacked on top of each other, it would be 2x the height of mt. Technically, there was no first human slow gradual change. Hence, no instant change from human to chimp. Populations become separated by a physical barrier and then evolve reproductive barriers: most common mode of speciation. Variant speciation: widespread population divided into two or more populations by wide spread populations by a physical barrier. Even if barrier disappears, species still might not be able to breed due to individual evolution. Small colony disperse from widespread species to new area and evolves reproductive isolation. Genetic drift argued as major factor differentiates new, small colony from parent population.